US 5,206,551 AGranted

Method for providing multi-level potentials at a sense node

AssigneeMicron Technology, Inc.

InventorWen-Foo Chern

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Abstract

Voltage sensing brings a sense node to three potentials by first grounding the node to a first potential equal to a reference potential and then floating the node to a substantially stabilized second potential equal to the reference potential plus a threshold voltage of an electrical device through which leakage current is pumped. The second potential is then decreased to a third potential greater than or equal to the first potential. The voltage sensing herein described typically is utilized in order to bias digit lines in a dynamic random access memory (DRAM) device during the active portion of the DRAM cycle and during an initiation of the precharge portion of the DRAM cycle. The second potential reduces the current leakage of the memory cell without utilizing an electrical device having a high threshold voltage. The initial momentary discharge of the sense node to the first potential allows a sense amplifier to behave like a conventional sense amplifier during initial sensing, thereby allowing a minimum digit/digit* sensing potential to approximate ground. Decreasing the second potential to a third potential at the initiation of the precharge cycle effects a decrease in the equilibrate potential of the digit lines, thereby increasing the "high logic window" as reflected in an increase in cell margin and a decrease in soft error rate (SER).

Claims18

Dependent claims

A method for effecting a potential at a sense node comprising:

a) charging a control input node of an initial electrical device toward a supply potential by coupling said control input node to a supply node through an actuated first switching device, said supply node capable of accepting said supply potential;
b) isolating the sense node from said supply node and a reference node, said reference node connectable to a reference potential;
c) charging the sense node to a generated potential by coupling the sense node to a generating means;
d) isolating the sense node from said generated potential;
e) isolating said control input node from said supply node by deactuating said first switching device;
f) actuating a second switching device to discharge said generated potential on the sense node through said initial electrical device and said second switching device, the sense node discharged to a first potential substantially equal to said reference potential;
g) pulling the sense node to a second potential equal to said first potential plus at least a threshold voltage of said initial electrical device;
h) maintaining said second potential;
and
i) discharging said second potential to a third potential less than said second potential, said discharging of said second potential to said third potential performed sufficiently later than said pulling said sense node to said second potential such that an interim time period exists during which the second potential remains at said second potential, said interim time period interposed between a time period wherein said first potential is effected at said sense node and a time period wherein said third potential is effected at said sense node, wherein said second potential is greater than said first potential and wherein said second potential is greater than said third potential.

7 more elements

A method for effecting a potential at a sense node comprising:

a) charging a control input node toward a potential of a supply node, said supply node connectable to a supply potential;
b) isolating the sense node from said supply node and a reference node, said reference node connectable to a reference potential;
c) charging the sense node to a generated potential by coupling the sense node to a generating means;
d) isolating the sense node from said generating means;
e) isolating said control input node from said supply node;
f) discharging said generated potential on the sense node, the sense node discharged to a first potential substantially equal to said reference potential;
g) pulling the sense node to a second potential equal to said first potential plus at least a threshold voltage of said initial electrical device;
h) maintaining said second potential;
and
i) discharging said second potential to a third potential less than said second potential, said discharging of said second potential to said third potential performed sufficiently later than said pulling said sense node to said second potential such that an interim time period exists during which the second potential remains at said second potential, said interim time period interposed between a time period wherein said first potential is effected at said sense node and a time period wherein said third potential is effected at said sense node, wherein said second potential is greater than said first potential and wherein said second potential is greater than said third potential.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/869,687Filed 15 Apr 1992 · continuation
Priority: 23 Aug 1991
Granted: 27 Apr 1993
Term ends: Not estimatedThe source records don’t support an estimate.

Classification3 codes

G11C 11/4091
Read-write [R-W] circuits: sense or sense/refresh amplifiers, or associated sense circuitry, e.g. for coupled bit-line precharging, equalising or…
G11C 7/06
Arrangements for writing information into, or reading information out from, a digital store: sense amplifiers; Associated circuits , e.g. timing…
G11C
Static stores